Method of using a single reactor for a plurality of conversions



May 7, 1957 S. C. EASTWOOD METHODOF USING A SINGLE REACTOR FOR APLURALITY OF CONVERSIONS Filed July 25. 1952 2 Sheets-Sheet l INVENTOR.5Y1. VANDEE 6 545701000 United States Patent METHOD OF USING A SINGLEREACTOR F OR A PLURALITY OF CONVERSIONS Sylvander Cecil Eastwood,Woodbury, N. 1., assignor to Socony Mobil Oil Company, Inc., acorporation of New York Application July 25, 1952, Serial No. 300,861

Claims. (Cl. 196-52) The present invention relates to hydrocarbonconversions and, more particularly, to a means whereby one reactor canbe used for the purpose of subjecting a hydrocarbon mixture to aplurality of conversions in the presence of the same particle-formcatalyst under a plurality of operating conditions of differentseverities.

Thus, for example, it is well-known that in general it is usual toprovide more severe conditions for reforming than for desulfurizing amixture of hydrocarbons. In the past, reforming and desulfurizing of thesame feed has been obtained employing the same catalyst but requiringtwo reactors or converters. It has now been discovered that a pluralityof conversions can be obtained in the same convertor or reactor bycontrolling the residence time and the reaction temperature.

It is an object of the present invention to provide a method ofoperating a single convertor to obtain desulfurization in one portion ofthe converter and reforming in another portion of the convertor whilstpassing the same particle-form solid contact material through both thereforming zone and the desulfurizing zone whilst maintainingsufiiciently severe conditions in the one zone to obtain reforming ofthe hydrocarbon charge stock therein and less severe conditions in thedesulfurizing zone to obtain practical desulfurization of thehydrocarbon charge stock therein. It is another object of the presentinvention to maintain the more severe conditions in the reforming zoneby supplying the major or controlling portion of the heat required inthat zone in the catalyst or particle-form solid contact material whilemain taining less severe conditions in the desulfurizing zone bysupplying the major or controlling portion of the heat required in thedesulfurizing zone in the hydrocarbon charge stock. It is a furtherobject of the present invention to facilitate the control of residencetime and reaction temperature in the desulfurizing zone throughbypassing effectively with respect to the hydrocarbon charge stock aportion of the catalyst entering the desulfurizing zone. It is alsowithin the scope of the present invention to provide means forcontrolling the residence time and reactor temperature in a plurality ofzones whereby a plurality of reactions in the presence of theparticleform catalyst can take place simultaneously. Other objects andadvantages will become apparent from the following discussion taken inconjunction with the drawings in which,

Figure l is a schematic illustration of one embodiment of the presentinvention in which a portion of the particle-form solid-contact materialor catalyst in one zone is by-passed with respect to the hydrocarboncharge stock; and

Figure 2 is a schematic illustration of another embodiment of thepresent invention in which a portion of the catalyst is by-passed in onezone;

Figure 3 is a schematic illustration of another embodiment of thepresent invention in which a portion of the 2,791,544 Patented May 7,1957 catalyst is not bypassed but reaction conditions are controlled bymeans of the catalyst-to-oil ratio.

It is generally accepted that the term desulfurization or "desulfurizingmeans reducing the sulfur content of a hydrocarbon charge stock. Onemethod known to the art is that of catalytic desulfurizing or catalyticdesulfurization. In catalytic desulfurizing a hydrocarbon charge stock,the charge stock is contacted with a suitable desulfurizing catalyst ofwhich many are known to the art at elevated temperatures in the presenceor absence of hydrogen or hydrogen containing gas for a period of timesuflicient at the temperature selected to reduce the sulfur content ofthe hydrocarbon mixture to a practical extent. A limitation upon thedesulfurizing conditions is the practical requirement that the lossthrough decomposition be kept low while achieving a reduction of thesulfur content necessary to provide prod ucts which will meetspecifications. Under such conditions, which relative to reformingconditions are relatively mild, the octane number of the charge stock isnot raised effectively.

It is generally accepted that the term reforming or aromatizing" orcyclizing is applied to a plurality of reactions occurringsimultaneously or successively or both, in which a primarily aliphatichydrocarbon charge stock is converted to a product having a higheroctane number and a higher content of aromatic hydrocarbons than thecharge stock.

For the desulfurizing conversion, the temperatures required are about650 F. to about 900 F. and preferably about 700 F. to about 800 F. Forthe reforming conversion the temperatures required are about 825 F. toabout 1025 F. and preferably about 875 F. to about 950" F.

The terms desulfurizing" or desulfurization and, reforming oraromatizing or cyclizing" are used herein in the sense briefly discussedhereinbefore.

In general, the present invention provides for a reforming zone and adesulfurizing zone in series relation through which the particle-formcatalyst passes as a compact column. That is to say, the catalyst passesthrough one zone as a compact column, enters the other zone and passestherethrough as a compact column. However, since the conditions in thedesulfurizing zone are much less severe than the conditions in thereforming zone, means must be provided for controlling the heat absorbedby the hydrocarbon charge stock in each zone to provide the severity ofconditions necessary to maintain desulfurization without excessive lossand reforming without excessive loss.

The catalyst leaves the kiln or regenerator at a temperature of about1000 to about 1100 F., and preferably about l000 to about 1050 F., andenters the first conversion zone at a temperature of about 975 to about1075 F. and preferably at about 975 to about 1025 F. In accordance withthe principles of the present invention, the reforming or desulfurizingtemperature is obtained in the respective zones by regulating the rateof the hydrocarbon stream to make either the catalyst or the hydrocarbonstream controlling of the temperature. In other words, the ratio ofcatalyst to oil is controlling. Thus, the stock to be desulfurized andreformed can enter at the lower end or bottom of the reactor having alower desulfurizing zone and an upper reforming zone and flows upwardcounter-current to downwardly flowing catalyst at a catalyst-to-oilratio such that the oil inlet temperature controls the temperature ofthe zone. In the upper or reforming zone the catalyst-to-oil ratio issuch that the catalyst inlet temperature is controlling.

In general, for producing reforming conditions, the catalyst-to-oilweight ratio, i. e., C/ H, is about 4 to about S and preferably about 4to about 6, and the Space velocity is about 1.0 to about 3.0 andpreferably about 1.5 to about 2.0 liquid volume of charge stock per unitvolume of catalyst in the reforming zone.

in the desulfurizing zone the charge stock inlet temperaturc is about650 to about 850 F. and preferably about 700 to about 800 F. Thecatalyst to oil weight ratio, i. c., C/H is about l.0 to about 3.0 andpreferably about 1.5 to about 2.0 and the space velocity is about 0.25to about 1.0 and preferably about .50 to about 0.75 liquid volume ofcharge stock per unit volume of catalyst in the desulfurizing zone.

in general, the reaction temperature in the dcsulfurizing zone is about650 to about 850 F., and preferably about 700 to about 800 F., while inthe reforming zone the reaction temperature is about 825 to about 1025F. and preferably about 875 to about 950 I.

Those skilled in the art will note that the catalyst-to-oil ratio in thedesulfurizing zone is lower than in the reforming zones. To achievethese ends one can either contact a given volume of charge stock with alesser volume of catalyst in the dcsulfurizing zone than in thereforming zone, or contact a lesser volume of hydrocarbons with a givenvolume of catalyst in the reforming zone than in the dcsulfurizing zone.

In the first alternative, a portion of the catalyst by passes thedcsulfurizing zone. In the second alternative, an auxiliary reformingzone can be employed or the reforming zone can have a catalyst volumeproportional to the catalyst volume of the desulfurizing zone. Forpractical reasons it is presently preferred to have the catalyst bypassthe desulfurizing zone.

Turning now to the drawings, the method of the pres cnt invcntion willbe described first by following the course of the catalyst through theprocess, then by following the hydrocarbon charge through the process.

Referring to Figure l and using as an illustrative example of the pluraltreatment of a reactant in a single multi-zone reactor the desulfurizingand reforming of a mixture of hydrocarbons containing hydrocarbonscapable of undergoing isoinerization. and/or dehydrogenation and/ordchydrocyclization. all of which molecular changes are includedgenerally in the designation, reforming, the course of the catalystthrough a plurality of zones, i. c., a desulfurizing zone and areforming zone will first be followed, and then the path of the mixtureof hydrocar' boos will be traced.

Active catalyst. for the purposes of the illustration--an alumina-silicacracking catalyst such as natural clays tfullers earth), treated naturalclays ("Super-Filtrol"), and synthetic associations of silica andalumina usually in gel form to which can be added other metals or metalcompounds for special purposes, is placed in feed bin 11. The catalystcan also be a group Vl metal or metal compound as ociated with aluminaor silica or in general any particle form catalyst which is suitable forproducing any one or all of the molecular changes generally denominated,"ison1erization." dehydrogenation and dehydrocyclization."

The catalyst at a temperature of about 950 to about 11 0 F. andpreferably at about 975 to about 1025 F. when using a cracking catalyst,flows from feed bin 11 through conduit 12 into surge chamber 13. Fromsurge chamber 13 the hot active catalyst flows through conduit 14 intoreactor 15 as a substantially compact column.

Reactor 15, as illustrated, is divided into two zones, an upperreforming zone 16 and a lower, annular desulfuriz ing zone 17. Zones 16and 17 are preferably of correlated volumes whereby the residence timeand/or the catalystto-oil ratio are correlated with the reactiontemperatures in both zones to provide the more severe reformingconditions in reforming zone 16 as compared to the relatively milddesulfurizing conditions in annular desulfurizing zone 17.

As illustrated in Figure 1, such correlated control is til) provided bythe catalyst by-pass 18. That is to say, the hot catalyst flows as asubstantially compact mass downwardly through reforming zone 16 to apoint such as "A" where the catalyst is divided into two portions, towit: a central stream which flows as a substantially compact columnthrough by-pass l8 and, as illustrated, an outer annular substantiallycompact hollow column 17.

By-pass 18 is of any suitable type whereby a portion of the catalystmass is separated from the rest of the catalyst flowing through thereactor and maintained out of effective contact with the reactant to betreated in the desulfurizing zone.

In the drawing Figure l, by-pass 18 is shown as a hollow, cylindricalcolumn provided at its lower end with a flaring skirt. Thecross-sectional area of the flared skirt is proportioned to the totalcrossscctional area of the reactor or catalyst column to divertsuihcient of the total catalyst column to provide in desulfurizing zone1.7 the catalyst-to-reactant ratio required to provide the milderconditions necessary in zone E7.

The catalyst to reactant ratio in zone 17 will be, as those skilled inthe art. know, dependent upon the temperature of the catalyst, thereaction temperature and the volume of reactant to be treated.

The by-passed catalyst flows as a substantially compact column throughby-pass 13. The balance of the catalyst: flows as a substantiallycompact annular column through annular zone 17. The two columns join inarea 41 at the bottom of the reactor and flow as a single substantiallycompact column from the reactor through conduit 19 to chute 20.

Generally, the catalyst in passing through the reactor becomes more orless inactivated. For economical reasons it is necessary to reactivatethe catalyst. in many catalytic reactions the catalyst can be r.i'ivated by combustion of the deactivating contamin: t in a stream ofcombustion-supporting gas. Since the reforming and dcsulfurizing of amixture of hydrocarbons results in the contamination of the catalystwith a carbonaceous deposit gcnerally called coke, the reactiwtion ofthe catalyst has been illustrated in Figure l as taking place in a kilnor regenerator 25. Accordingly, the deactivated catalyst flowing fromreactor 15 through conduit 19 passes into chute 20 and thence to anysuitable means for trans fcrring the deactivated catalyst to theregcncrator.

The catalyst transfer means can be .i it. an elevator or the likesuitable for transferring particle form catalyst from the reactor to aregenerator. As shown in Figure l in a schematic manner, the catalysttransfer means is an elevator, preferably a bucket elevator. The designof such and other catalyst transfer devices are so well-known to thoseskilled in the art as to require no description particularly since thepresent invention is not concerned with the design of catalyst transfermeans.

The deactivated catalyst passes through chute 20 to the boot 42 ofelevator 21. The deactivated catalyst is raised to head 43 of elevator21 and discharged into chute 22 along which the deactivated catalystflows to feed bin 23 of regenerator or kiln 25.

Regencrator or kiln 25 is of an "able design it herein the carbonaceouscontaminant or can be burned off in a stream of combustionsupporting gassuch as air. Since the present invention is not co ccrncd with thedesign of such regenerators or kilns an iucc the design of suchrcgencrators or kilns is well-kno to those sk lled in the art, thepresent invention is not limited to any particle lar regenerator.

The deactivated catalyst flows from 1' nor feed bin 23 through conduit24 into kilr ,c, in a heated stream of combustion-supporting gas such asair. the coke is burned-off at a temperature below the damagingtcrnperature at which the particular catalyst is deactivated in such amanner as to be practically useless a catalyst for the reaction. For thecatalysts of this illustration, the damaging temperature is in excess of1400 F. Conse quently, the temperature in kiln or regenerator is notgreater than about 1400 F. and can be as low as 950 F.

During passage through kiln 25 the coke deposit on the catalyst isburned-off and the catalyst reactivated. The hot reactivated catalystflows from the kiln through conduit 26 into chute 27 and thence to anysuitable catalyst transfer means whereby the reactivated catalyst israised to reactor feed bin 11. The catalyst transfer means can be a gaslift or the like, an elevator, etc. suitable for transferring catalystfrom chute 27 to reactor feed bin 11. As illustrated, the catalysttransfer means is a bucket elevator similar to that by which thedeactivated catalyst is transferred from reactor 15 to kiln 25. However,catalyst transfer means can be used to transfer the catalyst from thekiln to the reactor differing in type from that used to transfer thecatalyst from the reactor to the kiln.

As shown, the catalyst flows along chute 27 to elevator boot 44 ofbucket elevator 28 by which it is raised to head 45 of elevator 28. Fromhead 45 of elevator 28 the hot reactivated catalyst flows along chute 29to reactor feed bin 11 ready to begin another cycle.

It will be noted that the operation illustrated in a schematic manner inFigure 1 is one in which the reaction takes place at substantially thesame pressure as that at which the deactivated catalyst is regenerated.Those skilled in the art will recognize that when the reaction takesplace at a pressure higher than that at which regeneration is carriedout means must be provided to transfer the reactivated catalyst from azone of lower pressure to the zone of higher pressure and to transferthe deactivated catalyst from the zone of higher pressure to the zone oflower pressure. For example, when the reactor is operated atsuper-atmospheric pressure and the regenerator at a lower pressure, apressure lock is inserted between feed bin 11 and surge chamber 13 andbetween conduit 19 and chute 20.

The reforming and desulfurizing operations illustrated schematically inFigure 1 provide for counter-current flow of catalyst and reactant. Thecatalyst flows downwardly through zones 16 and 17 while the reactantflows upwardly. Thus, a mixture of hydrocarbons containing hydrocarbonswhich can be isomerized and/ or dehydrogenated and/or dehydrocyclicizedin the presence of a particle-form catalyst, for example, a virginnaphtha is drawn from a source not shown and passed through line 30 intofurnace 31. In furnace 31 the naphtha to be desulfurized and reformed isheated to a temperature such that at a pre-determined catalyst-to-oilratio and with the catalyst at a pre-determined temperature in zone 17,desulfurizing of the naphtha takes place. For example. with the catalystentering the desulfurizing zone at a temperature in the range of 850 to950 F., the virgin naphtha is heated to about 650 to about 850 F. andpreferably about 700 to about 800 F. in furnace 31. The heated naphthaleaves furnace 31 through line 32 under control of valve 35. The heatednaphtha is distributed over the cross-section of annular desulfurizingzone 17 by a distributor 46 of any suitable design. By regulating thecatalyst-to-oil ratio in annular zone 17, the reaction temperaturesuitable for desulfurizing the naphtha with substantially no loss ofnaphtha is maintained at about 650 to about 850 F. and preferably, atabout 700 to about 800 F.

The naphtha flows upwardly in annular zone 1) countercurrent to thedownwardly fiowing catalyst and during its contact with the catalyst isat least partially desulfurized upon entering reforming zone 16.

Upon entering reforming zone 16, the catalyst-to-oil ratio is changedbecause substantially all of the vapors of naphtha which contacted onlythe portion of the catalyst flowing through zone 17 new contacts thetotal volume of catalyst flowing through reforming zone 16.

The catalyst entering reforming zone 16 generally will have atemperature of about 975 to about 1075 F. and

preferably about 975 to about 1025 F. The catalyst enteringdesulfurizing zone 17 generally will have a temperature of about 850 toabout 950 F. The naphtha or other mixture of hydrocarbons to bedesulfurized and re formed entering zone 17 will have a temperature ofabout 650 to about 850 F. and preferably about 700 to about 800 F.

Under these conditions the catalyst-tomaphtha weight ratio, i. e., C/H,is about 4 to about 8 and preferably about 4 to about 6 in reformingzone 16 and about 1 to about 4 and preferably about 1.5 to about 2 inthe desulfurizing zone. Accordingly, by-pass 18 is of such dimensions asto by-pass sufficient catalyst to provide the requiredcatalyst-to-naphtha weight ratio. In other words. about 60 to about 75percent and preferably about to about percent of the catalyst from thereforming zone passes through bypass 18 while the balance, about 25 to40 and preferably about 30 to about 35 percent of the catalyst, is ineffective contact with the naphtha in desulfurizing zone 17.

The at-least-partially desulfurized naphtha flows upwardly throughreforming zone 16 where the molecular changes, generally classified asreforming, occur. The dcsulfurized and reformed naphtha flows fromreforming zone 16 through outlet 38, cooler 39 and line 40 to means forstabilizing and fractionating the effluent and subjecting the eflluentto such after-treatment as is necessary.

When it is desirable or necessary, the desulfurizing of the charge stockcan take place in the presence of hydrogen. For this purpose hydrogen orpreferably a hydrogen containing gas containing about 35 to aboutpercent hydrogen and the balance C1 to Ca hydrocarbons is drawn from asource not shown, heated in a furnace not shown to about 800 to about1100 F. and preferably to about 900 to about 1000" F. and drawn throughpipe 33 regulated by valve 36 and admixed with the charge stock in line32.

Similarly, when desired or required, the reforming reaction can takeplace, as is well-known, in the presence of hydrogen or a hydrogencontaining gas drawn from a source not shown through lines 33 and 34under control of valve 37, and introduced into reforming zone 16 throughone or more inlets and distributors not shown.

In the event that a recycle gas of low hydrogen content or devoid ofhydrogen or any other gaseous reactant or heat carrier is to be used inconjunction with a liquid reactant, the gaseous reactant can beintroduced into either or both zones by means of pipes 32 and 34.

Figure 2 is a schematic illustration of an arrangement of a plurality ofreaction zones in a single reactor or convertor through which a particleform catalyst flows successively wherein the reactant and catalyst flowconcurrently and the first zone through which the catalyst flows is thezone of relative mild reaction conditions and the second zone ofrelatively severe reaction conditions in contrast to the converse asillustrated in Figure 1.

As in Figure 1, the course of the catalyst will be followed through thereactor and then a description of the path of the reactant or reactantsthrough the reactor will be traced. For purposes of illustration, onlythe multizone single reactor is illustrated in Figure 2 since areforming and desulfurizing operation will be used for illustrativepurposes.

For purposes of illustration, a cracking and desulfurizing operationwill be described in which desulfurizing takes place under relativelymild conditions in desulfurizing zone 117 and cracking takes place incracking zone 116.

Hot active catalyst from a feed bin such as 11 flows into a surgechamber such as 13 and thence through con duit 114 into desulfurizingzone 117 of reactor 115. Desulfurizing zone 117 is preferably annular incross-section while by-pass 118 is circular. The cross-sectional areasof desulfurizing zone 117 and by-pass 118 are proportioned to provide acatalyst volume in zone 117 such that the catalyst-to-oil ratio is about1 to 3, and preferably 1.5 to 2.0, and a space velocity of about .25 to1.0 and preferably .5 to .75 when the catalyst enters the reactor at atemperature of about 975 to about 1075 F. and preferably about 975 toabout l025 F. and the oil to be desulfurized and cracked enters thedesulfurizing zone at about 650 to about 850 F. and preferably about 700to about 800 F. Under these conditions of reactant and catalyst inlettemperatures. catalyst-to-oil ratio and space velocity, the averagereaction temperature in desulfurizing zone 117 is about 650 to about 850F. and preferably about 700 to about 800 F.

In order to provide the catalyst-to-reactant ratio required in thedesulfurizing zone 117, about 60 to about 80, and preferably about 65 toabout 70 pcrccut of the catalyst stream entering reactor 115 flowsthrough bypass 118 and the balance, about to about 40 and preferablyabout to about percent flows as a substantially compact annular columnthrough desulfurizing zone 117.

The two substantially compact columns, the cylindrical column flowingdownwardly through by-pass 118 and the annular column flowing throughdesulfurizing zone 117 join at B and continue to flow downwardly as asingle compact column through cracking zone 116. When the catalystreaches the bottom of reactor 115, it is more or less deactivated with acarbonaceous contaminant generally called coke in the industry. Thedeactivated catalyst flows from the reactor through conduit 119 to suitable transfer means, and thence to a rcgencrator or kiln such as kiln 25of Figure l. The reactivated catalyst is then returned to the reactorfeed bin ready for another cycle through the reaction zones and theregenerator.

A mixture of hydrocarbons suitable for cracking and requiringdesulfurizing, such as a gas oil is drawn from a source not shownthrough line 130 and heated to at least a desulfurizing temperature infurnace 131. A temperature of about 650 to about 850 F. and preferablyabout 700 to about 800 P. will usually provide satisfactory results. Theheated oil is passed through line 132 under control of valve 135 todistributor 146 of any suitable design whereby the oil is distributedover the cross-section of annular desulfurizing zone 117.

The oil enters the desulfurizing zone at a temperature of about 650 toabout 850 F. and preferably about 700 to about 800 F. at such a rate toprovide a catalystto-oil ratio in desulfurizing zone 117 of about 1 toabout 4 and preferably about 1.5 to about 2.0 and a space velocity ofabout .25 to about 1.0 and preferably about .5 to about .75.

The oil flows concurrently downwardly with the substantially compacthollow cylinder or annulus of catalyst through desulfurizing zone 117.During this contact the oil is at least partially desulfurized. Thedownwardly flowing catalyst and reactant flow from desulfurizing zonc117 into cracking zone 116 where the reactant contacts not only thecatalyst from zone 117 but also the catalyst from by-pass 118. However,since the volume of catalyst effectively contacted by the volume ofreactant lea ing desulfurizing zone 117 is appreciably greater, thecatalyst-to-oil is increased and the temperature is in creased.Consequently, the reaction conditions are more severe. in the crackingzone 116 the catalyst-to-oil ratio is about 4 to about 8 and preferablyabout 4 to about 6 and the space velocity is about 0.5 to about 4.0 andpreferably about l.0 to about 2.0.

The eliluent from the desulliurizing zone flows concurrently downwardlywith the substantially compact column of catalyst through cracking zone116. The catalyst leaves zone 116 via conduit 119 while the vaporouscontents of zone 116 leave by way of line 138 to pass through cooler 139and line 140 to after-treatment, stabilizing and fractionating equipmentnot shown.

When desirable or necessary, a gaseous heat carrier or a gaseousreactant can be mixed with the heated liquid reactant in line 132. Sucha gas can be drawn from a source not shown through line 133 undercontrol of valve 136. Furthermore, when necessary, a gaseous heatcarrier or reactant can be introduced into cracking zone 116 throughpipe 134 and its associated distributor not shown under control of valve137.

Since, for purposes of illustration, the desulfurizing and cracking of agas oil has been described, those skilled in the art will understandthat the catalyst can be any suitable cracking catalyst such as naturalclays, such as fullcr's earth, treated clays such as Supcr-Filtrol, synthetic associations of alumina and silica usually in gel form with orwithout other metals or metal compounds; added for special purposes andthe like.

Figure 3 provides a schematic illustration of It means for carrying outtwo reactions with the same catalyst under different conditions ofseverity wherein the capacity of the zone in which the less severeconditions prevail is appreciably greater than the capacity of the zonewherein the more severe conditions prevail. As before, the course of thecatalyst through reactor 215 and auxiliary reactor 246 will he followedand then the course of the vaporous reactants through reactor 215 andauxiliary reactor 246 will be traced.

Hot active catalyst in bin 211 flows through conduit 212 into surgechamber 213. From surge chamber 223 hot activc catalyst flows intoconduits 214 and 2H. tn the event that the capacity of zone 216 issufficient to handle the total reactant from zone 21'? of reactor 255.conduit 244 is provided with a suitable shut-oii valve 24!.

The hot active catalyst, for the purpose of illustration and descriptiona cracking catalyst having reforming characteristics, flows as a compactcolumn along conduits 214 and 244 to reactors 215 and 246 respectively.The hot active catalyst flows downwardly as u substtur tially compactcolumn through both reactors 21S and 246 counter'current to vaporousreactant flowing upwardly.

The catalyst flows downwardly in reforming zone 216 of reactor 215 Wherethe temperature of the catalyst is about 825 to about 1025 F. andpreferably about 875 to about 950 F.

In order to obtain a reforming reaction. the space w:- locity of thevaporous reactant entering reforming zones 216 and 263 is about 1.0 toabout 3.0 preferably ab t 1.5 to about 2.0 and the catalyst-to-liquidreactant wei h ratio is about 4 to about 8 and preferably about 4 toabout 6.

The total catalyst in reforming zone 216 passes through seal legs 262into desulfurizing zone 217 wherein the space velocity is about .25 toabout 1.0 and preferably about .5 to about .75 and thecatalyst-to-liquid reactant weight ratio is about 1 to about 4 andpreferably about 1.5 to about 2.0. Under these conditions, the Ali (11reaction temperature in desulfurizing zone 217' is about 650 to about850 F. and preferably about 700 in about 800 F.

The total catalyst flowing into reforming zone 2.63 flows downwardly asa substantially compact column through reforming zone 263 of reactor 246to leave the reactor via conduit 247 and chute 255 to a catalyst tram;-fer means.

The total catalyst flowing through zone 217 icavcs rcactor 215 byconduit 219 and thence along chute to any suitable catalyst transfermeans whereby the den vated catalyst is transferred to a regenerator orkiln it h as kiln 25 of Figure 1. Such a catalyst transfe" Fil llllw canbe an elevator, gas-lift or the like.

The catalyst from both reactors 215 and 246 is trans ferred by asuitable catalyst transfer means, not shown, to a regenerator, notshown, reactivated and return :t! to feed bin 211 in any suitablemanner.

A mixture of hydrocarbons suitable for reforming and requiringdesulfurizing, such as a mixture of hydrocarbons capable ofisomerization and/or dehydrogenation and/or dehydrocyclization, forexample-a virgin naphtha, is drawn from a source, not shown, throughline 230, heated in furnace 231 and the heated oil discharged intodesulfurizing zone 217 of reactor 215 through line 232 and associateddistributor 266 under control of valve 235.

Distributor 266 is of any suitable type whereby the heated reactant,naphtha, can be distributed over the cross-section of desulfurizing zone217.

The naphtha is heated to a temperature of about 650 to about 850 F. andpreferably to about 700 to about 800 F. in furnace 231 and entersdesulfurizing zone 217 at about the temperature at which it leavesfurnace 231.

The heated naphtha flows upwardly counter-current to the downwardlyflowing substantially compact column of catalyst at a catalyst-to-oilweight ratio of about 1.0 to about 4.0 and preferably about 1.5 to about2.0 and at a space velocity of about 0.25 to about 1.0 and preferably ofabout 0.50 to about 0.75. During contact with the catalyst at an averagetemperature of about 650 to about 850 F. and preferably about 700 toabout 800 F. produced by correlation of catalyst temperature, naphthetemperature, catalyst-to-naphtha weight ratio and space velocity, thenaphtha is at least partially desulfurized.

The desulfurized naphtha leaves desulfurizing zone 217 by line 248. Whenthe entire effluent from desulfurizing zone 217 can be adequatelytreated in reforming zone 216, the entire effluent passes through lines248 and 249 (with valve 251 closed) to distributor 256 which is of anysuitable type whereby the effiuent can be distributed over thecross-section of reforming zone 216.

When the entire eflluent from desulfurizing zone 217 cannot beadequately treated in reforming zone 216, a portion is diverted throughvalve 251 and line 250 to reforming zone 263 of reactor 246. When thequantity so diverted is insufiicient to be efiiciently reformed inreforming zone 263 additional low sulphur naphtha such as a crackednaphtha can be drawn from a source not shown through line 258 heated toa reforming temperature in furnace 259, discharged therefrom throughline 260 under control of valve 261 into distributor 257 where it ismixed with the portion of effluent from desulfurizing zone 217 whichenters distributor 257 from line 250.

The efiluent from desulfurizing zone 217 is introduced into reformingzone 216 and the etlluent or effluent and additional naphtha isintroduced into reforming zone 263 at a rate such that thecatalyst-to-naphtha ratio is about 4 to about 8 and preferably about 4to about 6 and the space velocity is about 1.0 to about 3.0 andpreferably about 1.5 to about 2.0.

The vaporous reactants flow upwardly from distributors 256 and 257through reforming zones 216 and 263 counter-current to a downwardlyflowing substantially compact column of catalyst in each reforming zone.

The effiuent from reforming zone 216 passes through line 238 to line254. The effluent from reforming zone 263 passes through line 252 toline 254. The mixed effluents then pass through cooler 239 and line 240to after-treatment, stabilization and fractionation.

When the capacity of reforming zone 216 is such as to adequately treatthe total effluent from desulfurizing zone 217 and reactor 246 is not inoperation valve 253 is closed.

When it is desired or necessary, both reactions can be carried out inthe presence of a gas. Thus, for example, the desulfurizing can becarried out in the presence of hydrogen or a hydrogen-containing gas.Similarly, the reforming reaction can be carried out in the presence ofhydrogen or a hydrogen-containing gas. Furthermore, for some purposes itcan be desirable to supply heat to either or both zones by means of agaseous or vaporous carrier. For such purposes, a suitable gas can bedrawn from a source not shown through pipe 233 and passed into pipe 232under control of valve 236 and thence into desulfurizing zone 217.Similarly, a gas can be passed from pipe 233 through pipe 234 undercontrol of valve 237 to reforming zone 216. Likewise, a gas can bepassed from pipe 233 through pipe 264 under control of valve 265 intoreforming zone 263.

Thus, for example, in accordance with the principles of the presentinvention, a blend of 50 volume percent coker gasoline and 50 volumepercent straight run heavy naphtha having a boiling range of 128 to 433F. was treated as described hereinbefore. The effluent of thedesulfurizing zone at various desulfurizing temperatures produced withan oil inlet temperature of 629 to 962 F. at the space velocitiesindicated was obtained in yields noted and with the sulfur content andoctane numbers listed in Table I.

TABLE I Run No l I 2 F 3 4 1 5 0 Average Desulfurizing Ternperature, "F929 825 765 1500 972 097 Sulfur percent Weight, Desul- Iurizing ZoneEffluent. 0. 18 0. l7 0. 17 0. 21 0.26 0. 29 Yield of Er'fiuent, percentvolume 77.9 93 95 77. 8 82. 3 Space Velocity.... 0. 5 0. 5 0.5 0.5 0. 12. 0 Catalyst-to-nnphtha w lght ratio 4.1 4. 2 4. 2 4.8 4.1 4.2 Octanenumber or Effluent I from Desulfurizing zone 75. 0 69 61. 5 (i0 74. 874. 6 Octance number of Eifiuent 3 cc. TEL... S6. 4 81 75. 5 74. 5 86. 085. 0 Percent Sulfur Rcmovcd.. 66 68 68 00 51 45 Sulfur content offee-.l-tddesulfurizing zone 0.53 Weight percent. Research octane rat'mgof the feed was 01.5 clear and 72.0 with 3 cc. TEL.

I Research.

2 Research +3 cc. TEL.

It will be noted that runs numbers 2, 3 and 4 were made atdesulfurization temperatures of 690 to 825 F. and at relatively lowspace velocities while runs Nos. 1, 5 and 6 were made at desulfurizationtemperatures in excess of 900" F. at space velocities of 0.5, 1.0 and2.0. Nevertheless, the yield of desulfurized oil of comparable grade wasfar greater, i. e., in excess of 90 volume percent in the runs made atlow temperatures and low space velocities than the yield of desulfurizedoil in the runs made at high temperatures and low space velocities orhigh temperatures and high space velocities. Accordingly, it ispreferred to operate at temperatures of about 700 to about 800 F. in thedesulfurizing zone.

When the afore-described efiluents are then reformed as describedhereinbefore, the finished products are obtained in the yields and withthe octane numbers indicated in Table II.

TABLE II Run No. 4 Average reforming temperature F 970 Yield reformate,volume percent on charge of desulfurizing zone eflluent 80.0 Spacevelocity 1.5 Catalyst-to-oil weight ratio 4.5 Octane number of reformate1 75.0 Octane number of reformate+3 cc. TEL 87.0

1 Research. Research +3 cc. TEL.

Those skilled in the art will understand that the auxiliary reformingzone 263 can have a capacity just sufficient to treat the portion ofefliuent from desulfurizing zone 217 in excess of that which can betreated in reforming zone 216 or reforming zone 263 can have a capacitysuch as to treat an additional low sulfur naphtha or the like as well asor simultaneously with the efiluent from desulfurizing zone in excess ofthat which can be treated in reforming zone 217.

In view of the foregoing description and discussion, it is believedapparent to those skilled in the art that the present invention providesa means for carrying out a plurality of reactions at different reactionconditions of temperature and residence time in a plurality of zones ina reactor through which a single catalyst or a mixture of catalystsflows successively as a substantially compact column and that thereaction condition in the difierent zones are controlled, regulated andmaintained by controlling the catalyst-to-reactant weight ratio, thespace velocity and correlating the aforesaid with the catalyst andreactant temperatures to provide different reaction temperatures in eachzone. Specifically, the present invention provides for desulfurizing andreforming a mixture of hydrocarbons under relatively severe reformingconditions in one zone and desulfurizing the same mixture ofhydrocarbons under relatively less severe conditions in a second zone bycontrolling, regulating and maintaining a different catalyst-to-reactantweight ratio and a different space velocity in each zone. Thus, forexample, a reforming catalyst, for example, a chromiaalumina or amolybdena-alumina reforming catalyst, can be used at reformingtemperatures and pressures of about 850-l080 F., preferably about 875 to1060 F., and about 25600, preferably about 100 to 300 p. s. i. a. in thepresence of about l-l5, preferably about 4-10 mols of recycle gas permol of naphtha or about l-8, preferably about 25 mols of hydrogen at aspace velocity of about 0.1-6.0, preferably about 0.5-2.0, volumes ofliquid charge stock per volume of catalyst in the reforming zone. Thecharge stock is desulfurized at a temperature of about 650-850 F.,preferably about 700 to about 800 F. in the presence of the reformingcatalyst used in the reforming zone.

ltclaim:

l. A process for desulfurizing and reforming a hydrocarbon mixture in asingle multi-zone reactor which comprises introducing activeparticle-form catalyst, said catalyst combining activity for reformingwith activity for hydrogenation of organically combined sulfur in ahydrocarbon mixture to hydrogen sulfide, at a temperature of about 950F. to about ll F. into a single multi-zone reactor. flowing saidcatalyst through a reforming zone, flowing a portion of said catalystfrom said reforming zone to and through a by-pass zone. flowing thebalance of said catalyst through a desulfurization zone, introducing ahydrocarbon mixture to be desulfurized and reformed into saiddesulfurization zone at a temperature of about 650 F. to about 850 F.,flowing said hydrocarbon mixture at a liquid space velocity of about0.25-l .0 v./v./hr. through said desulfurization zone in contact withsaid balance of said catalyst to at least partially desulfurize saidhydrocarbon mixture and to lay down a carbonaceous deposit on saidcatalyst, flowing at least partially desulfurized hydrocarbon mixturefrom said desulfurizing zone into and through said reforming zone at aspace velocity of about l.03.0 v./v./ hr. in contact with said catalystto reform said at least partially desulfurized hydrocarbon mixture andto lay down a carbonaceous deposit on said catalyst, withdrawingreformed and desulfurized hydrocarbon mixture from said reforming zone,withdrawing catalyst contaminated with carbonaceous deposit from said(lesulfurizing zone and from said by-pass zone, regenerating and heatingsaid withdrawn catalyst to a temperature of about 950 F. to about ll00F. by combustion of said carbonaceous deposit, regulating the flow ofcatalyst and at least partially desulfurized hydrocarbon mixture throughsaid reforming zone to provide a catalyst to oil ratio of about 4 to 8to maintain a reaction temperature of about 825 F. to about 1025 F. insaid reforming zone, and regulating the flow of catalyst and hydrocarbonmixture through said dcsulfurizing zone to provide a catalyst to oilratio differout to the aforesaid catalyst to oil ratio and about 1 to 4to maintain a reaction temperature of about 650 F. to about 850 F. insaid desulfurizing zone.

3. A process for catalytically cracking and desulfuriziug a hydrocarbonmixture in a single multi-zone reactor which comprises introducing hotactive particle form solid catalyst which combines activity forconverting hydrocarbons boiling above the gasoline range intohydrocarbons boiling in the gasoline range with activity forhydrogenating organically combined sulfur in said hydrocarbon mixture tohydrogen sulfide at a temperature of about 975 F. to about 1075 F. intoa multi-zone reactor, flowing a portion of said catalyst through aby-pass zone, flowing the balance of said catalyst through adesulfurizing zone, flowing a stream of catalyst from said by-pass zone,flowing a stream of catalyst from said desulfurizing zone, combiningsaid flowing streams of catalyst, introducing said combined flowingstreams of catalyst into a catalytic cracking zone, introducinghydrocarbon mixture to be desulfurized and catalytically cracked intosaid desulfurizing zone at a temperature of about 650 F. to 850 F.,flowing said hydrocarbon mixture at a liquid space velocity of about0.25 to 1.0 v./v./hr. through said desulfurizing Zone in contact withsaid catalyst to produce an at least partially desulfurized hydrocarbonmixture and to lay down a carbonaceous deposit on said catalyst, flowingsaid at least partially desulfurized hydrocarbon mixture through saidcracking zone at a liquid space velocity of about 0.5 to 4.0 v./v./hr.to produce a catalytically cracked and at least partially desulfurizedhydrocarbon mixture and to deposit on said catalyst at carbonaceousdeposit, withdrawing cracked and at least partially desulfurizedhydrocarbon mixture from said catalytic cracking zone, withdrawingcatalyst con taminated with carbonaceous deposit from said catalyticcracking zone, regenerating and heating said catalyst to a temperatureof at least about 975 F. to about 1075 F. by combustion of saidcarbonaceous deposit, regulating the flow of said balance of catalystthrough said desulfurizing zone to provide a catalyst to oil ratio ofabout 1 to 4 to maintain said desulfurizing zone reaction temperature atabout 650 to about 850 F. and regulating the flow of the combinedstreams of catalyst from desulfurizing zone and said by-pass zonethrough said cracking zone to provide a catalyst to oil ratio differentto the aforesaid catalyst to oil ratio and about 4 to 8 to maintain saidcracking zone reaction temperature.

3 A process for reforming and desulfurizing a hydrocarbon mixture whichcomprises introducing active particleforrn solid catalyst at atemperature of about 825 F. to about l075 F. into two reforming zones Aand B, said catalyst combining activity for reforming hydrocarborn withactivity for hydrogenating organically combined sulfur in a hydrocarbonmixture to hydrogen sulfide, flowing said catalyst through saidreforming zones, flowing catalyst from said reforming zone A only intoand through a desulfurizing zone, introducing a hydrocarbon mixture atabout 650 to about 850 F. into said desulfurizing zone, flowing saidhydrocarbon mixture through said desulfurizing zone in contact with saidcatalyst to provide an at least partially desulfurized hydrocarbonmixture and to produce a carbonaceous deposit on said catalyst,regulating the flow of said hydrocarbon mixture through saiddesulfurizing zone to provide a liquid space velocity of 0.25 to l .0v./v./hr. and to provide a catalyst to oil ratio of about l-4 tomaintain a reaction temperature of about 650 F. to about 850 F,introducing said at least partially desulfurized hydrocarbon mixtureinto said reforming zones A and B, proportioning the feed of at leastpartially desulfurized hydrocarbon mixture to said reforming zones A andB to provide a liquid space velocity of about 1 to about 3 v./v./hr. ineach of said reforming zones while providing a catalyst to oil ratio ineach of said zones A and B different to the aforesaid catalyst to oilratio and about 4 to about 8 to maintain a reaction temperature of about825 to about l025 H. flowing said partially desulfurizcd hydrocarbonmixture through said reforming zones in contact with said catalyst toproduce a reformed desulfurized hydrocarbon mixture and to produce acarbonaceous deposit on said catalyst, withdrawing reformed desulfurizedhydrocarbon mixture from said reforming zones, withdrawing catalystcontaminated with carbonaceous deposit from said reforming zone B,withdrawing catalyst contaminated with carbonaceous deposit from saiddesulfurizing zone,

13 combining said withdrawn catalyst, regenerating and heating saidcatalyst to a temperature of about 825 F. to about 1075 F. by combustionof said carbonaceous deposit, and recycling said heated catalyst to saidreforming zones.

4. In the method for subjecting hydrocarbon mixtures to at least twodifferent conversions in a plurality of reaction zones, one of saidreaction zones being at a higher temperature than the other whichcomprises introducing a given quantity particle-form catalytic materialcatalyzing the reaction in all reaction zones at at least said highertemperature into one of a plurality of reaction zones, flowing saidgiven quantity of particle-form catalytic material through all of saidreaction zones, contacting all of said given quantity of particle-formcatalytic material with reactant in each of said reaction zones,regulating the fiow of reactant to each of said reaction zones andregulating said given quantity of particle-form catalytic material toestablish relatively mild reaction conditions in one of said reactionzones and relatively severe reaction conditions in the others of saidreaction zones, the improvement which comprises contacting only a partof said given quantity of pm'ticle-form catalytic material with reactantin the reaction zone under relatively mild reaction conditions.

5. The improvement in the process of claim 4 wherein the reactantcontacts only about 60 to about 80 percent of the given quantity ofcatalytic material in the zone under relatively mild reactionconditions.

References Cited in the tile of this patent UNiTED STATES PATENTS2,417,308 Lee Mar. ll, 1947 2,418,672 Sinclair et a1 Apr. 8, 19472,418,673 Sinclair et all. Apr. 8, i947 2,437,222 Crowley et al Mar. 2,1948 2,439,730 Happel Apr. 13. 194R 2,642,38l Dickinson June 16, i9532,692,903 Haehmuth Oct. 26, 1954 2,724,683 Nadro Nov. 22, 1955

2. A PROCESS FOR CATALYTICALLY CRACKING AND DESULFURIZING A HYDROCARBONMIXTURE IN A SINGLE MULTI-ZONE REACTOR WHICH COMPRISES INTRODUCING HOTACTIVE PARTICLE FORM SOLID CATALYST WHICH COMBINES ACTIVITY FORCONVERTING HYDROCARBONS BOILING ABOVE THE GASOLINE RANGE INTOHYDROCARBONS BOILING IN THE GASOLINE RANGE WITH ACTIVITY FORHYDROGENATING ORGANICALLY COMBINED SULFUR IN SAID HYDROCARBON MIXTURE TOHYDROGEN SULFIDE AT A TEMPERATURE OF ABOUT 975*F. TO ABOUT 1075*F. INTOA MULTI-ZONE REACTOR, FLOWING A PORTION OF SAID CATALYST THROUGH ABY-PASS ZONE, FLOWING THE BALANCE OF SAID CATALYST THROUGH ADESULFURIZING ZONE, FLOWING A STREAM OF CATALYST FROM SAID BY-PASS ZONE,FLOWING A STREAM OF CATALYST FROM SAID DESULFURIZING ZONE, COMBININGSAID FLOWING STREAMS OF CATALYST, INTRODUCING SAID COMBINED FLOWINGSTREAMS OF CATALYST INTO A CATALYST CRACKING ZONE, INTRODUCINGHYDROCARBON MIXTURE TO BE DESULFURIZED AND CATALYTICALLY CRACKED INTOSAID DESULFURIZING ZONE AT A TEMPERATURE OF ABOUT 650*F. TO 850*F.,FLOWING SAID HYDROCARBON MIXTURE AT A LIQUID SPACE VELOCITY OF ABOUT0.25 TO 1.0 V./V./HR. THROUGH SAID DESULFURIZING ZONE IN CONTACT WITHSAID CATALYST TO PRODUCT AN AT LEAST PARTIALLY DESULFURIZED HYDROCARBONMIXTURE AND TO LAY DOWN A CARBONACEOUS DEPOSITE ON SAID CATALYST,FLOWING SAID AT LEAST PARTIALLY DE-